Why is DOM manipulation not just handled by another module in the module/mediator/facade pattern?

I've just finished listening to Nicholas Zakas's great talk on the module/mediator/facade design pattern. I want to use this pattern for an upcoming project, but I've got a question that I can't nut out:

Why does Zakas let the DOM manipulation and AJAX communication be handled by the application core? Given the philosophy of the design pattern, couldn't these just be treated as modules?

I feel like the fact that I'm asking this means that I misunderstand something fundamental about the module/mediator/facade design pattern. Hopefully someone can fill me in.